Outer cover of pneumatic tires.



J. G. BARKER.

OI ITER COVER OF PNEUMATIC TIRES.

APPLICATION 111.1111 11011.5.1910.

1,004,344. Patented Sept 26, 1911.

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JOHN CHARLES BARKER, 0F LEEDS, ENGLAND.

OUTER.C OVER' 0F PNEUMATIC TIRES;

Specification of Letters Patent. Patented Sept, 26, 1911,

application filed November 5, 1910. Serial No, 590,833,

To all whom it may concern:

Be it known that I, JOHN Cumulus BAR KER, a subject of the King of Great Britain and Ireland, residing at Leeds, in the county of -York, England, have invented certain newand useful Improvements in the Outer Covers of Pneumatic Tires; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art towhich it a ertaius to make and use the same.

T is invention relates to the formation of raised portions on the tread surface of the outer covers of pneumatic tires, withthe object of insuring a better grip on the read both for propulsion of, the vehicle and for preventing side slipping.

This invention is hereunder described with reference to the accompanying drawing, in Which- Figure 1 is a view of part of the tread surface of the outer cover of a pnuematic tire, and Fig. 2 is a section on line A B of Fig. 1..

As the invention is applicable to any of the usual kinds of outer covers for pneumatic tires, at cross section of the cover is omitted.

According to this invention the tread surface is divided by recesses or grooves d into a series of rhomboidal raised sections as indicated by the b "aces f f, each of which latter is divided by the grooves or recesses e into, a larger raised part a, two smaller raised parts 0 and two lettered 1.) intermediate in size. The direction of the recesses cl makes an angle of about 37 degrees with the side of the tire, and that of the recesses e of about 50 degrees with the side of the tire. The width of both the recesses and projections is roughly one third the tread width of the tire. The outside corners of the rectangle fbrmed by the larger projections are cut oil by the sides of the tread. There are thus no angular corners directed outward, only flat broad surfaces, which ollfcr a more ellectual resistance to side slipping, while the recesses (Z and (1 offer a relatively large space for the escape of wet and greasy material between them, enabling the edges of both the longer and the shorter of the projections on the side toward which slipping is taking place, to bite more readily on the underlying firmer ground. The elongated rhomboidal form of the sections into which the tire is divided, as above described, coupled with the relatively large width of the projections and recesses, destroys the close uniformity produced bymore regular geometrical patterns of projections and grooves; in which the latter are more liable to be clogged up with material tightly embedded in the recesses, especially Where these have no outlet. This will be evident on comparing the supportmg surface ofi'ered inthe neighborhood of the small triangular projections 0 and that offered about the approxin'iately rectangular projections a. #This deviation from close uniformity thus enhances the gripping power of the wheel for propulsion of the car. The device otl'ers the same resistance to slipping toward both sides of the tire.

I am aware that recesses or grooves in the tread portion of the outer cover pf pneu matic tires running diagonally in opposite directions across the tread have previously been used for increasing the grip on the road and preventing side slipping, I therefore make no general claim to such, but

What I do claim is 1. A pneumatic tire provided with an outer cover having a tread portion constructed of a series of rhomboidal raised sections, integral with the tire, each divided by grooves into a larger raised part forming an approximately rectangular projection with the outer opposite corners cut oil two smaller triangular projections, and two in termcdiate sized projections having a truncated rectangular shape; the width of the projections being roughly one third the width of the tread surface of the tire, the projections and also said rhomboidal sections being separated from each other by grooves approximately of the same width as the projections.

The combination to *orm the tread portion of the outer cover of a pneumatic tire of a series of projections separated by two series of grooves of LIPIHOXllUlLlUlY the same width as ll c projections, running slantwisc completely across the tread oi. the lire in opposite directions; the one series at an angle of about 37 degrees with the sides of the tire, the circlunfercntial pitch of the same being about two and one half times the width of the tread portion of the tire; and the other scries'al an angle of about 55 degrees to the sides of the tire with a circumferential pitch about five sixths the width of the tire. 3. A tire having a tread comprising two series of grooves crossing each other and a series of intervening raised parts, some of which extend obliquely across the tread at In testimony whereof, I have signed my regular intervals having the form of elonname to this specification in the presence of gated rectangular parallelograms with two two subscribing Witnesses.

' of their corners cut off by the borders of the JOHN CHARLES BARKER.

tread, the intervening projecting parts hav- IVitnesses: ing the forms of lesser fragments of a rec- J. CLARK JEFFERSON,

tangle cut at difierent points by said borders. WM. S. EDMONDSON. 

